Topical vaginal sustained delivery of siRNA presents a significant challenge due to the poor stability of the current formulations.

To overcome this problem, researchers at ULg (Brigitte Evrard’s Laboratory, CIRM) have developed a novel drug delivery system capable to adhere to the vaginal mucosa. The new polymeric solid mucoadhesive system was designed as such that rehydration occurs in situ by the vaginal fluids to form a hydrogel. This technology allows to deliver, in a sustained manner, mucopenetrating pegylated lipoplexes releasing the siRNA to the vaginal tissues.

To minimize adhesive interactions with vaginal mucus components, lipoplexes were coated with derivatives of polyethylene glycol (DSPE-PEG2000) and incorporated in hydroxyethyl cellulose (HEC) hydrogels.  In order to avoid drug degradation and to obtain a solid and easy to handle system, the hydrogels containing pegylated lipoplexes were freeze-dried.

Frequency of application is reduced by combining muco-adhesion and prolonged drug delivery resulting in an increased patient compliance.